Hyperbaric Medicine in Neurological Disease Robert C. Barnes, MD, FACP Infectious Diseases and Hyperbaric Medicine Sacred Heart Medical Center Riverbend Springfield , Oregon
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“The bends” caused annual mortality of 25% of caisson workers on the East Hudson tunnel
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78 y/o male with aortic valvular dysfunction and atrial fibrillation underwent AoVR with root replacement and MAZE procedure with left atrial ligation. Postoperatively found to have flaccid left hemiparesis with myoclonic jerking. CT perfusion study showed decrease in cerebral blood flow in the right hemispheric white matter c/w watershed pattern. Neurological consultation : Course c/w arterial gas embolism. Patient currently three months after event with residual left hemiparesis with dysphagia requiring tube feeds, pressure ulcers, indwelling urinary catheter, atrial fibrillation, orthostatic hypotension and inability to transfer.
Gas Embolus Epidemiology • May occur autocthonously from decompression injury or externally from iatrogenic introduction • May be venous, or arterial if shunt or pulmonary filtration overwhelmed • Incidence of macrovascular CAGE during cardiac bypass surgery ~ 0.1% • 2.65/100,000 hospitalizations, with 1-year mortality 21% Refs: Ghosh PK et al J Cardiovasc Surg (Torino) 1985; 26: 248-50 Bessereau J et al Intensive Care Med 2010; 36: 1180 -7
I atrogenic Gas Embolus Causes • Highest risk sugeries: • Seated craniotomy • C-section • Hip replacement • Cardiac bypass • Other causes: • Central or peripheral IV leak • Pulmonary/ventilator barotrauma • Insufflation • TURP/prostatectomay • Upper airway laser YAG laser • Lung biopsy • Contrast injection • Carotid endarterectomy
Iatrogenic Causes of Gas Embolization Hennepin County Marseille CVC leak or removal = 9 56 Cardiac bypass = 4 14 Carotid injection = 3 5 Lung biopsy = 2 other = 11 1 Pulmonary barotrauma = • 8 of 9 with venous AGE source had CXR changes c/w pulmonary edema vs 0 of 9 with arterial source • Only 26% of head CTs or TTEs showed intravascular gas • All patients with GCS = 3 before HBO2 died Refs: Benson J et al. Undersea Hyperbaric Med 2003; 30: 117-26; Blanc, ibid.
Bubble I njury in Gas Embolus • Threshold for venous-to-arterial air to cerebral circulation without PFO: • > 20 ml bolus or • 11 ml/min infusion
Bubble I njury Affected neurons Flow Endothelial irritation Inflammation and vasogenic edema From: Muth CM, Shank ES. NEJM 2000;342:476-82 • Mechanical occlusion with downstream hypoxia • PMN adhesion and degranulation with vessel injury and activation of inflammation with resultant edema Areas of bubble migration reflect cardiac output to end organs. Cerebral emboli typically involves 30-60 micron dia small arteries
Causes and Treatment of Gas Embolism Venous gas Paradoxical Arterial gas embolism embolism embolism Right Left Central line Paradoxical embolism Cause manipulation I njection of air during Shunting Seated craniotomy imaging procedures Barotrauma Surgery Laparoscopy Lung biopsy Cardiac bypass Hemodialysis Central line introduction Others 100% Oxygen Hyperbaric Oxygen Hyperbaric Oxygen Treatment From: Fukaya E, Hopf HW. Neurological Res 2007; 29:143
Effects of HBO2 in Intravascular Bubbles Immediate effect: Reduces bubble size and decreases vascular occlusion
Effect of Pressure on Bubble Size Percent Atmospheres Absolute
Effects of HBO2 in Intravascular Bubbles Non-immediate effects: • Increases O 2 – bubble gradient, leading to exchange of metabolically active O 2 for N 2 • Increases O 2 to ischemic tissue • Decreases PMN adhesion and vascular damage by down-regulating ICAM-1/beta-integrin receptors • Decreases cerebral edema and ICP
Diagnosis of CAGE • Imaging insensitive • Clinically • Prolonged anesthesia recovery • Cardiac arrest • Hemiparesis, especially left –sided • Decreased LOC • Hypotension • Chest pain/dyspnea/Cheyne-Stoke breathing • “Mill wheel” splashing murmur • ?Transcranial doppler
Time to Hyperbaric Oxygen Treatment of Gas Embolus and Outcome: Conventional Wisdom Full recovery or minor sequelae in 83% of gas emboli treated within 6 hours vs 53% with greater delay. No difference in outcome with delay in arterial gas embolization. [N = 86; Recovery = 67% venous, 35% arterial] But: Delay < 6 Hours > 6 Hours % Venous 84% 16% % Arterial 53% 47% Ref: Blanc P. Intensive Care Med 2002; 28: 559
Time to Hyperbaric Oxygen Treatment of Gas Embolus and Outcome REF N= Clinical Average Delay % Fully % Mortality/ / Recovered Severe Deficit Diver Leitch & Green, 1986 89 D < 10 min 65% 1% / 16% Pearson & Goad, 1982 5 D 20 min 80% 20% / 0 Kol et al 1993 6 C 3 h [2-20] 50% 33% / 17% Blanc et al 2002 86 C 3.5 h [2-8] 58% 8% / 9% Murphy et al 1985 16 C 8 h [0.2-25] 50% 12% / 6% Neuman % Hallenbeck, 1987 4 D 9 h [1-15] 75% 0 / 0 Ziser et al, 1999 17 C 9.6 h [1-20] 47% 18% / 35% Takahashi et al, 1987 34 C 13 h [0.5-40] 62% 24% / 0 Massey et al, 1990 14 C 17.5 h [1-48] 50% 22% / 14% Betterman & Melamed, 1988 6 C 24 h [11–60] 33% 33% / 0 Muskat et al, 1995 4 C 26 h [3-48] 75% 25% / 0 Ref: Van Hulst RA, Klein J, Lachmann B. Clin Physiol Funct Imaging 2003; 23:237
Adjunctive Treatment of CAGE • Avoid glucose-containing IV fluids (Lanier WL et al Anesthesiology 1987; 66:39) • Avoid steroids (may increase ischemic injury) • Avoid heparin (? Decreases injury in animal models, but fear of ICH) • Use phenobarbital (Decreased O2 demand, decreases ICP, decreases catecholamine release) and phenytoin • Consider lidocaine 1.5 mg/kg load then gtt [Reduces infarct size in animal models with decreased cognitive loss if give for 48 h after valve replacement surgery (Mitchell, 1999)]
Case #1 : 78 y/o diabetic woman presents with fever, facial paralysis and right retroorbital pain two weeks after right- sided otalgia and otorrhea. A small cholesteotoma and a large amount of granulation tissue were observed in the EAC. She had received several short “courses” of antibiotics, but continued to be febrile. Two months after first noticing the fever and pain, she was transferred to a referral center and in early August a CT showed A/F level in the mastoid with “thickening” of the middle ear space. No bony erosion was noted. She underwent a surgical debridement, with negative bacterial cultures. When 8 weeks of treatment with Unasyn did not improve her pain and fever, she was transferred to VMMC.
Temporal bone CT 10/02/04 showed right OE and OM, marked sclerosis of the mastoid remnant, medial inferior temporal and sphenoid bone, erosion of the right mandibular head, and cortical thinning of the clivus. 99 Tc scan 10/05/04 showed increased uptake in right mastoid region and clivus, but SPECT not done due to patient movement. Findings similar found on 67 Ga citrate scan at the same time.
Otogenic Skull Base Osteomyelitis • Usually in elderly diabetics • Male:female ratio 1:1 • Trivial trauma such as hearing aids lead to portal (?) • Usually occurs weeks to months after NEO treatment • Pseudomonas aeruginosa is such a predominate pathogen that empirical treatment is justified • No standard duration for therapy, but is no longer a surgical disease
Otogenic Skull Base Osteomyelitis: Presentation • Follows NEO by weeks to months • Spreads not through aerated bone, but by septic venous thrombosis and along subfascial planes, so cranial nerve presentation can be early • Persistent pain, usually headache, is most frequent symptom. Residual otalgia, otorrhea, hearing loss may be present, along with new CN deficits • Fever, like in NEO, usually absent • Tenderness may be less than in NEO • WBC infrequently elevated, ESR elevated in majority
Otogenic Skull Base Osteomyelitis Cranial Nerve Presentation VII NEO local effect Facial paresis X Foraminal effect Dysphonia, dysphagia XI Shoulder weakness IX choking, aspiration, vocal weakness Infection of petrous pyramid V Sensory effects/neuralgia III, IV, VI Diplopia
Why do diabetics get NEO? • Cerumen pH is increased to ~7.0 • PMNs exhibit impaired chemotaxis and phagocytosis • Monocytes and macrophages have decreased phagocytosis • Decreased oxidative burst and killing • Defects are not reversed by tight glycemic control
Skull Base Osteomyelitis: Etiology • Malignant otitis externa • Bacteremia/sphenoiditis/tuberculous petrositis • Penetrating (usually) trauma • Fungal otic invasion • Paranasal sinus contiguous spread
Non-otogenic Skull Base Osteomyelitis • No pathognomonic signs or imaging; surgery to r/o neoplasm is the rule • Staph aureus the most common bacterial agent. Coag – Staph, Candida, and Pseudomonas next in frequency • Patient often bacteremic and toxic, with prominent fever and early CN signs (particularly VI) • IDU is frequently reported in bacteremic sphenoiditis Ref: Malone DG et al. Neurosurg 1992; 30: 426-31.
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